Coated roofing insulation and roofing systems including such insulations

ABSTRACT

A single ply membrane roofing system includes a roofing insulation board which, preferably, is at least 45% by dry weight expanded perlite. One major surface of the insulation board is coated with a latex coating comprising, by dry weight, between 48.3% and 96% clay; between 3.1% and 33.3% latex; and between 0% and 34% sodium silicate. A single ply roofing membrane is adhered to the coated major surface of the insulation board with a roofing contact adhesive.

This patent application is a continuation-in-part of pending patentapplication Ser. No. 09/251,060, filed Feb. 18, 1999.

BACKGROUND OF THE INVENTION

The present invention relates to roofing insulation used in single plyroofing membrane systems, and, in particular, to roofing insulationboards coated on a major surface with a latex containing coating toimprove the adherence of single ply roofing membranes to the roofinginsulation boards.

Single ply roofing membrane systems are commonly used as roofing systemsfor low sloping roofs, especially in industrial and commercialapplications. Typically, these single ply roofing membrane systemsinclude roofing insulation boards, such as but not limited to perliteinsulation boards, wood fiber insulation boards, glass fiber insulationboards, polymer foam insulation boards, and composite insulation boardsmade up of two or more layers of different materials, such as perlitebased, wood fiber based, glass fiber based and polymer foam boardlayers. These roofing insulation boards are secured to the roof deck bymechanical fasteners or other conventional means. Of the above listedroofing insulation boards, perlite roofing insulation boards, such asperlite insulation boards sold by Johns Manville International, Inc.,under the trademark FESCO®, have several advantages over the other typesof roofing insulation boards. For example, these perlite roofinginsulation boards are typically lower in density and absorb less waterthan wood fiber roofing insulation boards and, the high inorganiccontent of the perlite roofing boards, renders the perlite roofinginsulation boards much less flammable than the typical wood fiberroofing insulation boards.

A single ply roofing membrane, such as but not limited to membranes madeof ethylene propylene diene terpolymer rubber (EPDM), ethylene propylenerubber (EPR), and alloys of ethylene propylene diene terpolymer rubber(EPDM) or ethylene propylene rubber (EPR) with polypropylene(thermoplastic olefin elastomers or TPO's) or poly(vinyl chloride),overlay and are secured to the upper major surfaces of the roofinginsulation boards by conventional mechanical fasteners or withcommercially available roofing contact adhesives. These single plyroofing membranes may or may not include reinforcing meshes or scrimslocated intermediate layers of the material forming the single plyroofing membrane.

SUMMARY OF THE INVENTION

The present invention relates to roofing insulation boards having uppermajor surfaces which are coated with a latex containing coating toimprove the bond between the overlaying single ply roofing membrane andthe roofing insulation boards when the overlaying single ply roofingmembranes are adhesively bonded to the roofing insulation boards and toroofing systems incorporating such coated roofing insulation boards. Toimprove the bond between the upper major surface of the insulation boardand the single ply roofing membrane, the upper major surface of theinsulation board is coated with a coating including, by dry weight,between 48.3% and 96% filler; between 3.1% and 33.3% latex; and 0% to34% sodium silicate.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic, partial vertical cross section through a singleply roofing membrane system incorporating a coated roofing insulationboard of the present invention.

FIG. 2 is a schematic, partial vertical cross section through a singleply roofing membrane system incorporating a coated composite roofinginsulation board of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

As shown in FIGS. 1 and 2, the single ply roofing membrane system of thepresent invention 20 indudes roofing insulation boards 22 that arecoated on their upper major surfaces with a latex containing coating 24to enhance the adhesion of a single ply roofing membrane to theinsulation boards. The roofing insulation boards are nailed or otherwisesecured to a roofing deck 26 by conventional mechanical fasteners. Thesingle ply roofing membrane system 20 also indudes a single ply roofingmembrane 28 overlaying the roofing insulation boards 22 and bonded tothe coated upper major surfaces of the roofing insulation boards by aconventional roofing contact adhesive 30. Preferably, the single plyroofing membrane is fully adhered to the upper major surfaces of theroofing insulation boards. The term “fully adhered”, as used herein,means the single ply roofing membrane is attached or secured to thesubstrate with 100% of the area which the single ply roofing membraneoverlays having the specified bonding adhesive.

The roofing insulation boards 22 used in the single ply roofing membranesystem 20 indude, as shown in FIG. 1, perlite or wood fiber insulationboards; and, as shown in FIG. 2, composite insulation boards which canindude a layer 32 of polymer foam board, such as isocyanurate foamboard, and/or a layer of glass fiber board in addition to a layer ofperlite or wood fiber board 34. When composite roofing insulation boards22 are used, the board layers 34 forming the upper major surfaces of theroofing insulation boards, the surfaces to which the single ply roofingmembrane 28 is adhered, should be either perlite based or wood fiberbased and, preferably, perlite based. These insulation boards 22 aretypically 2 by 4 feet, 4 by 4 feet, or 4 by 8 feet in width and lengthand typically range from about ½ of an inch to about 1½ inches inthickness. While the wood fiber roofing insulation boards and compositeroofing insulation boards including glass fiber insulation board layersand/or polymer foam insulation board layers can be used in the singleply roofing membrane system 20, perlite based insulation boards arepreferred. The perlite insulation boards are typically lower in densitythan the wood fiber insulation boards. While the wood fiber insulationboards typically have a density ranging from about, 18 to about 22pounds per cubic foot (pcf), the perlite insulation boards typicallyhave densities ranging from about 8 to about 14 pcf. In addition, theperlite insulation boards absorb less water than the wood fiberinsulation boards. Due to the high inorganic content of the perliteinsulation boards, the perlite based insulation boards are lessflammable than the wood fiber insulation boards.

The perlite based insulation boards 22, preferred for use in the singleply roofing membrane system 20, include, by dry weight, about 45% toabout 76% expanded perlite; about 15% to about 45% cellulosic fibers;about 0.1% to about 10% latex binder, about 2% to about 9% bituminousmaterial; and 0% to about 3% alum and, preferably, about 50% to about72% expanded perlite; about 23% to about 35% cellulosic fibers; about 1%to about 8% latex binder; about 2% to about 9% bituminous material; and0% to about 3% alum. While other cellulosic fibers can be included inthe product, e.g. up to about 45% by dry weight of the fibers in theproduct, preferably, the cellulosic fibers are recycled newsprintfibers. As used herein, the term recycled newsprint fibers also includesrecycled telephone book fibers and similar fibers.

The perlite particles used in the preferred insulation boards 22 areexpanded perlite particles preferably having a density of about 3 toabout 6 pounds per cubic foot. Since the expanded perlite particles areinorganic, the expanded perlite particles contribute to the fireresistance of the insulation board. In addition, the perlite particleshave excellent thermal insulating properties and greatly enhance theoverall thermal insulating properties of the insulating boards.

The cellulosic fibers are used in the preferred perlite insulationboards 22 primarily for the strength that the cellulosic fibers add tothe insulating board through the hydrogen bonding between the cellulosicfibers and an interfelting of the cellulosic fibers with the expandedperlite particles which assists in holding the expanded perliteparticles in place within the insulation boards. The cellulosic fibersalso act as a bulking material to maintain the pedite insulation boardswithin the desired density range for such products.

The bituminous material in the preferred perlite insulation boards 22provides the insulation boards with a greater resistance to waterabsorption and also assists the cellulosic fibers in holding theexpanded perlite particles in place within the insulation boards.Preferably, the expanded perlite partides are pre-coated with thebituminous material before being introduced into the slurry of the wetforming operation. While other bituminous materials could be used in theperlite insulation boards 22, asphalt is the preferred bituminousmaterial. Asphalt is economical, readily available and performs well inthe perlite insulation boards 22.

The polymeric binder in the preferred perlite insulation boards 22 canbe any of numerous commercially available latex binders which functionto assist in holding the interfelted fibers and expanded perliteparticles together in the insulation board and, preferably, improve thestrength of the perlite based insulation board relative to perlite basedinsulation boards of comparable thickness, width, length and densityusing starch binders. Of the latex binders, the preferred latex bindersare acrylic latex binders, poly(vinyl acetate) latex binders, andstyrene/butadiene rubbers (SBR), such as but not limited to Dow DL 242NASBR; BF Goodrich HYCAR 26138 acrylic; BF Goodrich HYCAR 26288 acrylic;Omnova Solutons GenFlo 8045 carboxy modified SBR polymer; and BFGoodrich GOODRITE SB706 SBR.

Other perlite insulation boards 22 which can be used in the single plyroofing membrane system 20, include by dry weight, about 45% to about76% expanded perlite; about 15% to about 45% cellulosic fibers; about0.1% to about 10% starch binder, about 2% to about 9% bituminousmaterial; and about 0% to about 3% alum. Except for the starch binder(e.g. unmodified com starch), the ingredients of these perliteinsulation boards are the same as those used in the preferred perliteinsulation boards with the latex binder.

The latex containing coating 24 on the upper major surface of theinsulation boards 22 is preferably coextensive with the upper majorsurface of the insulation boards and weighs in dry weight about 1.1grams per square foot (g/ft²) to about 12.0 g/ft². Coatings 24 appliedin amounts, dry weight, less than 1.1 g/ft² to the upper major surfacesof the insulation boards 22 may not provide sufficient coverage tosufficiently enhance the adherence of a single ply elastomeric roofingmembrane 28 to the upper major surfaces of the insulation boards 22.Coatings 24 applied in amounts, dry weight, more than 12.0 g/ft² to theupper major surfaces of the insulation boards 22 do not further enhancethe adherence of a single ply elastomeric roofing membrane 28 to theupper major surfaces of the insulation boards 22 and increase the costof the coated insulation boards 22. Preferably, the coating 24 isapplied in amounts, dry weight, of about 4.5 g/ft² to about 9.0 gft².

The coating includes, by dry weight, about 48.3% to about 96% filler,about 3.1% to about 33.3% latex; and 0% to about 34% sodium silicate,and preferably, by dry weight, about 62% to about 85% filler, about 8%to about 21% latex; and about 4% to about 21% sodium silicate.Preferably, the filler is kaolin day and examples of latexes which maybe used in the coating are: poly(vinyl acetate) latexes; acryliclatexes, and styrene/butadiene rubber latexes. A preferred latex isGenFlo 8045 carboxy modified SBR polymer manufactured by OMNOVAsolutions. The sodium silicate in the coating provides the coating witha generally harder surface and may improve adhesion between the uppermajor surface of the roofing insulation boards 22 and the single plyroofing membrane 28.

The single ply roofing membrane 28 may be any of a number ofcommercially available single ply roofing membranes, such as but notlimited to membranes made of ethylene propylene diene monomer rubber(EPDM), ethylene propylene diene terpolymer rubber (EPDM), ethylenepropylene rubber (EPR), and alloys of ethylene propylene dieneterpolymer rubber (EPDM) or ethylene propylene rubber (EPR) withpolypropylene (thermoplastic olefin elastomers or TPO's) or poly(vinylchloride). These single ply roofing membranes may be reinforced withreinforcing meshes or scrims 36 (e.g. polyester reinforcing meshes orscrims) located intermediate layers of the material forming the singleply roofing membrane.

The adhesives 30 used to bond or adhere the single ply roofing membrane28 to the coated upper major surfaces of the roofing insulation boards22 are commercially available roofing contact adhesives, such as but notlimited to solvent based neoprene bonding cement, water based acrylicbonding cements, solvent based Nibile Rubber bonding cements. Theseadhesives are generally applied to the upper coated major surfaces ofthe roofing insulation boards 22 in amounts, dry weight, ranging fromabout 10 to about 20 g/ft² .

To test the adhesive bond between the coated insulation boards andsingle ply roofing membranes, laboratory samples of the preferredperlite insulation boards disclosed above, using starch and latexbinders, were made by repulping cellulosic fiber (source of fiber wassurplus #1 News) in a hydropulper with warm water at approximately 120°F. The fiber was then collected and dewatered to about 20% solids. Theactual solids determination was done by drying a small sample overnight.Laboratory boards were made using a Williams 14 inch×14 inch hand sheetformer. The desired amount of pulp was stirred into about thirty poundsof water and allowed to mix for three minutes. Asphalt emulsion was thenadded and allowed to stir for one minute. The binder (starch or latex)was added and mixed for two minutes. The pH was then checked andadjusted with alum to a pH of 5.3 to 5.8. At least 12 ml of alum (20%)was added to all formulations, regardless of the pH. The expandedperlite was then added and was mixed for thirty seconds beyond the pointwhere all of the perlite was wetted-out. The slurry was then transferredto the Williams apparatus and the water was allowed to substantiallyfree drain until the edges of the slurry pulled away from the headboxsidewalls, then vacuum was applied for forty-five seconds. The wet boardwas then pressed to 1′ or ½′ for two minutes and the latex containingcoating of the present invention was applied to a major surface of thesamples (about 10 to about 40 g wet/ft² or about 1.1 to 12.0 g dry/ft²).The coated wet board was then passed twice through a conveyed forced airoven at about 400° F. (total residence time about one and one halfhours) to dry the board and the coating. The perlite board and thecoating were then dried at 250-270° F. overnight or over a weekend.

In addition to the laboratory samples, perlite insulation boards ofvarious thicknesses and having the formulations disclosed above werealso made for the tests on a conventional, commercial Fourdriniermanufacturing line. In the process newsprint fibers are broken downthrough the action of warm water and mechanical mixing in a hydropulpercreating a slurry which is stored in a holding tank or chest. Theexpanded perlite used in the formulation is produced by rapidly heatingperlite ore in perlite expanders. When the perlite insulation board ismade with a latex binder, the asphalt emulsion (a waterproofing agent),alum (retention aid), expanded perlite and latex binder are added to theslurry with the latex binder being added to the slurry after the asphaltemulsion has been added and prior to the addition of the otheringredients. When the perlite insulation board is made with a starchbinder, the asphalt emulsion (a waterproofing agent), alum (retentionaid), expanded perlite and starch binder are added to the slurry withthe starch binder being added last. In addition, a poly(acrylamide)retention aid diluted (inverted) prior to use (sold by Nalco ChemicalCompany, under the trademark Nalco 7520) was added via a separate pumpin conjunction with the binder. The resulting mixture passes through ahead box and is distributed uniformly over a continuously moving wirebelt of the Fourdrinier machine where excess water is allowed tofree-drain by gravity. The semisolid slurry (about 75% water at thispoint) was then sized to the approximate thickness with either a secondwire or a felt belt. More water was then removed with the help of anapplied vacuum to form a wet mat. The coating of the present inventionwas then applied to a major surface of the wet mat by spraying orrolling the coating material onto the major surface (about 10 to about40 g wet/ft² or about 1.1 to 12.0 g dry/ft²). The wet, coated perliteboard formed was then cut into mats and passed through a multi-deck,multi-zone dryer, e.g. a Coe dryer, for the completion of the dryingprocess. The speed of the production line, as well as the temperaturesof the different zones in the dry, vary with the density and thicknessof the periite insulation board being made. After exiting the dryer, theperlite insulation boards were cut into desired sizes by trim saws.

The relative strengths of the adhesive bonding of single ply roofingmembranes 28: a) to the major surfaces of the laboratory and productionline perlite boards, coated with the latex containing coating 24 setforth in Table I, below, and b) to uncoated major surfaces of wood fiberand isocyanurate foam roofing insulation boards, were estimated bymeasuring the peel resistances or strengths, set forth in Table II,below, of two inch wide strips of single ply roofing membrane adhered tothe major surfaces of the boards with conventional, commerciallyavailable roofing contact adhesive applied in amounts between 10 and 20grams dry/ft². Higher peel resistances or strengths were presumed toindicate better bonding between the single ply roofing membranes and themajor surfaces of the insulation boards. Uncoated perlite insulationboards exhibited peel resistances in pounds per inch ranging from about0.50 to about 0.94.

TABLE I COATING FORMULATIONS USED ON PERLITE BOARDS % % % % LATEX LATEX% SODIUM WATER CLAY #1 #2 SILICATE LABORATORY SAMPLE 1 80 10 5 5 2 73 152 10 3 58 25 2 15 4 58 25 10 10 5 75 15 10 6 75 15 10 7 70 25 2 3 8 7315 2 10 PRODUCTION SAMPLE T1-1 T1-2 80 10 5 5 T2-1 T2-2 78 15 7 T3-1T3-2 85 15 4 CLAY - kaolin LATEX #1 - GenFlo 8045 carboxy modified SBRpolymer - about 50% solids LATEX #2 - GenFlo 2000 - about 50% solidsSODIUM SILICATE - about 38% solids

TABLE II PEEL RESISTANCE FOR FULLY ADHERED SINGLE PLY MEMBRANES PEELPEEL RESIST- RESIST- LABORATORY ANCE PRODUCTION ANCE SAMPLE (LB/IN)SAMPLE (LB/IN) 1 4.35 T1-1 2.78 2 2.66 T1-2 1.74 3 3.31 T2-1 2.25 4 3.78T2-2 3.15 5 5.10 T3-1 1.94 6 2.91 T3-2 1.94 7 0.23 8 3.19 UNCOATED 1.38UNCOATED 2.48 ISOCYANURATE ISOCYANURATE FOAM FOAM UNCOATED 0.33 UNCOATED1.06 REGULAR DENSITY REGULAR DENSITY WOOD FIBER WOOD FIBER UNCOATED 0.95HIGH DENSITY WOOD FIBER

In describing the invention, certain embodiments have been used toillustrate the invention and the practices thereof. However, theinvention is not limited to these specific embodiments as otherembodiments and modifications within the spirit of the invention willreadily occur to those skilled in the art on reading this specification.Thus, the invention is not intended to be limited to the specificembodiments disclosed, but is to be limited only by the claims appendedhereto.

What is claimed is:
 1. A roofing insulation board for use in single plyroofing membrane system, comprising: an insulation board; the insulationboard having a first major surface to which a single ply roofingmembrane is adhered when the insulation board is installed in a singleply roofing membrane system; and the first major surface of theinsulation board having a latex coating; the latex coating comprising,by dry weight, about 48.3% to about 96% filler; about 3.1% to about33.3% latex; and 0% to about 34% sodium silicate.
 2. The roofinginsulation board according to claim 1, wherein: the dry latex coatingweighs between 1.1 grams and 12.0 grams per square foot.
 3. The roofinginsulation board according to claim 2, wherein: the filler is kaolinclay and the latex is selected from a group consisting of acryliclatexes; poly(vinyl acetate) latexes and styrene/butadiene rubberlatexes.
 4. The roofing insulation board according to claim 3, wherein:the insulation board comprises, by dry weight, the followingingredients: about 45% to about 76% expanded perlite; about 15% to about45% cellulosic fibers; about 0.1% to about 10% latex binder; about 2% toabout 9% bituminous material; and 0% to about 3% alum.
 5. The roofinginsulation board according to claim 3, wherein: the insulation boardcomprises, by dry weight, the following ingredients: about 45% to about76% expanded perlite; about 15% to about 45% cellulosic fibers; about0.1% to about 10% starch binder; about 2% to about 9% bituminousmaterial; and 0% to about 3% alum.
 6. The roofing insulation boardaccording to claim 1, wherein: the filler is kaolin day and the latex isselected from a group consisting of acrylic latexes; poly(vinyl acetate)latexes and styrene/butadiene rubber latexes.
 7. The roofing insulationboard according to claim 6, wherein: the insulation board comprises, bydry weight, the following ingredients: about 45% to about 76% expandedperlite; about 15% to about 45% cellulosic fibers; about 0.1% to about10% latex binder; about 2% to about 9% bituminous material; and 0% toabout 3% alum.
 8. The roofing insulation board according to claim 6,wherein: the insulation board comprises, by dry weight, the followingingredients: about 45% to about 76% expanded perlite; about 15% to about45% cellulosic fibers; about 0.1% to about 10% starch binder about 2% toabout 9% bituminous material; and 0% to about 3% alum.
 9. The roofinginsulation board according to claim 1, wherein: the latex coatingcomprises, by dry weight, about 62% to about 85% filler; about 8% toabout 21% latex; and 4% to about 21% sodium silicate.
 10. The roofinginsulation board according to claim 9, wherein: the filler is kaolin dayand the latex is selected from a group consisting of acrylic latexes;poly(vinyl acetate) latexes and styrene/butadiene rubber latexes.
 11. Asingle ply membrane roofing system, comprising: a roofing insulationboard; the insulation board having a first major surface; a first majorsurface of the insulation board having a latex coating thereon; thelatex coating comprising, by dry weight, about 48.3% to about 96%filler; about 3.1% to about 33.3% latex; and 0% to about 34% sodiumsilicate; and a single ply elastomeric roofing membrane adhesivelyadhered to the first major surface of the insulation board.
 12. Theroofing system according to claim 11, wherein: the dry latex coatingweighs between 1.1 grams and 12.0 grams per square foot.
 13. The roofingsystem according to claim 12, wherein: the filler is kaolin clay and thelatex is selected from a group consisting of acrylic latexes; poly(vinylacetate) latexes and styrene/butadiene rubber latexes.
 14. The roofingsystem according to claim 13, wherein: the insulation board comprises,by dry weight, the following ingredients: about 45% to about 76%expanded perlite; about 15% to about 45% cellulosic fibers; about 0.1%to about 10% latex binder; about 2% to about 9% bituminous material; and0% to about 3% alum.
 15. The roofing system according to claim 13,wherein: the insulation board comprises, by dry weight, the followingingredients: about 45% to about 76% expanded perlite; about 15% to about45% cellulosic fibers; about 0.1% to about 10% starch binder, about 2%to about 9% bituminous material; and 0% to about 3% alum.
 16. Theroofing system according to claim 11, wherein: the filler is kaolin clayand the latex is selected from a group consisting of acrylic latexes;poly(vinyl acetate) latexes and styrene/butadiene rubber latexes. 17.The roofing system according to claim 16, wherein: the insulation boardcomprises, by dry weight, the following ingredients: about 45% to about76% expanded perlite; about 15% to about 45% cellulosic fibers; about0.1% to about 10% latex binder, about 2% to about 9% bituminousmaterial; and 0% to about 3% alum.
 18. The roofing system according toclaim 16, wherein: the insulation board comprises, by dry weight, thefollowing ingredients: about 45% to about 76% expanded perlite; about15% to about 45% cellulosic fibers; about 0.1% to about 10% starchbinder, about 2% to about 9% bituminous material; and 0% to about 3%alum.
 19. The roofing system according to claim 11, wherein: the latexcoating comprises, by dry weight, about 62% to about 85% filler; about8% to about 21% latex; and 4% to about 21% sodium silicate.
 20. Theroofing system according to claim 19, wherein: the filter is kaolin dayand the latex is selected from a group consisting of acrylic latexes;poly(vinyl acetate) latexes and styrene/butadiene rubber latexes.